Solution

2) Two solutions

a) Helpmate in four

b) Helpmate in five exactly.

Black moves first.

a)

1... Kh2
2.f3 Kg3
3.Na3 Kf4
4.g3+ Ke3
5.Nc2 Mate

b)

1... Kh2
2.f4 Kg3
3.e3 Kg4
4.Ke2 Kf5
5.g4+ Ke4
6.Nc3 Mate

The second mate is shifted one square further up the board. A chameleon echo.